The invention relates to improvements in an apparatus for pneumatically transporting a file or row of successive rod-shaped articles lengthwise between a sender and a receiver. More particularly, the invention relates to improvements in an apparatus which can be utilized with advantage for pneumatic transport of rod-shaped articles of the tobacco processing industry, especially for pneumatic transport of filter rod sections of unit length or multiple unit length. For example, the pneumatic transport according to the invention can move filter rod sections from a filter rod making machine to the magazine of a so-called tipping machine wherein the filter rod sections are united with rod-shaped tobacco-containing articles to form filter cigarettes, cigars, cigarillos or the like. As a rule, the filter rod sections or articles which reach the receiver are caused to move sideways, e.g., into the aforementioned magazine of the tipping machine.
As a rule, a pneumatic conveyor for a file of successive rod-shaped articles (hereinafter mainly referred to as sections or filter rod sections) comprises an elongated pneumatic conduit defining an elongated path (such path can include straight as well as arcuate portions) for successive sections of the file. The conduit has a receiving end which accepts successive sections from the sender, and a discharge end which delivers successive sections to the receiver. As a rule, the conduit receives and advances a file of successive sections which may but need not be of identical length, and the number of conveyed sections per unit of time may but need not be constant, depending on variations of output of the maker of filter rod sections and/or upon fluctuations of the requirements of the consumer of filter rod sections. It is desirable to ensure that the distance or spacing between successive sections in the pneumatic conduit remain at least substantially constant, i.e., within a certain acceptable range of distances. Actual conveying takes place by means of a pressurized fluid, normally compressed air, and the pressure of the fluid influences the achievement of or the failure to achieve the aforementioned desired parameters including the establishment of and adherence to an optimum distance between successive sections of the file of such sections in the conduit.
In the event of a malfunction, e.g., a malfunction involving fluctuations in the rate of transport which are attributable to the sender and normally involve a reduction of the rate of transport of sections per unit of time, a conventional apparatus is likely to develop undesirable changes in the rate and manner of receiving successive sections at the discharge end of the conduit; this can result in an undesirable interruption of the delivery of sections or in an equally undesirable pile-up of sections at the discharge end of the conduit.